DJ-1 controls T cell differentiation and osteoclastogenesis in rheumatoid arthritis

Osteoimmunology in Osteoarthritis: Unraveling the Interplay of Immunity, Inflammation, and Joint Degeneration

Osteoarthritis (OA) is a degenerative joint disease influenced by multiple factors, with its etiology arising from intricate interactions among mechanical stress, inflammatory processes, and disruptions in bone metabolism. Recent research in bone immunology indicates that immune-mediated mechanisms significantly contribute to the progression of OA, highlighting the interactions among immune cells, cytokine networks, and bone components. Immune cells interact with osteoclasts, osteoblasts, and chondrocytes in a variety of ways. These interactions foster a pro-inflammatory microenvironment, contributing to cartilage breakdown, synovial inflammation, and the sclerosis of subchondral bone. In this article, we present a comprehensive review of bone immunology in OA, focusing on the critical role of immune cells and their cytokine-mediated feedback loops in the pathophysiology of OA. In addition, we are exploring novel therapeutic strategies targeting bone immune pathways, including macrophage polarization, T-cell differentiation, and stem cell therapy to restore the metabolic balance between immunity and bone. By integrating cutting-edge research in bone immunology, this review integrates the latest advancements in bone immunology to construct a comprehensive framework for unraveling the pathogenesis of OA, laying a theoretical foundation for the development of innovative precision therapies.

The role of Th/Treg immune cells in osteoarthritis

Osteoarthritis (OA) is a prevalent clinical condition affecting the entire joint, characterized by its multifactorial etiology and complex pathophysiology. The onset of OA is linked to inflammatory mediators produced by the synovium, cartilage, and subchondral bone, all of which are closely tied to cartilage degradation. Consequently, OA may also be viewed as a systemic inflammatory disorder. Emerging studies have underscored the significance of T cells in the development of OA. Notably, imbalances in Th1/Th2 and Th17/Treg immune cells may play a crucial role in the pathogenesis of OA. This review aims to compile recent advancements in understanding the role of T cells and their Th/Treg subsets in OA, examines the immune alterations and contributions of Th/Treg cells to OA progression, and proposes novel directions for future research, including potential therapeutic strategies for OA.

PH-sensitive BSA-modified resveratrol micelles targeting macrophages alleviate symptoms of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, leading to severe inflammatory infiltration and joint damage, accompanied by a decrease in pH of joint microenvironment. Macrophages play an important role in the pathogenesis of RA, with high expression of bovine serum albumin (BSA) receptors on the surface of macrophages. Resveratrol (Res) has strong anti-inflammatory effects, but its application is limited due to its poor water solubility and low bioavailability. Therefore, we constructed pH-sensitive micelles by encapsulating Res and modifying BSA on the surface of the micelles (BSA-Res@Ms), thereby greatly improving the therapeutic effect of RA. Our research results indicated that BSA-Res@Ms had a smooth and uniform appearance, small particle size, high drug encapsulation efficiency, good stability, and pH-sensitive properties. In vitro, BSA-Res@Ms increased the uptake of Res by RAW264.7 cells, reduced the levels of pro-inflammatory cytokines and cleared excess ROS produced by activated RAW264.7 cells, and inhibited the generation of osteoclasts. In vivo, BSA-Res@Ms could target inflamed joint sites, significantly alleviate joint inflammation symptoms, inhibit activated macrophages, improve synovial hyperplasia and inflammatory cell infiltration, and protect cartilage. BSA-Res@Ms provide a very promising method for the treatment of RA, which can effectively improve the inflammatory manifestations of RA.

Research progress of targeted therapy regulating Th17/Treg balance in bone immune diseases

Rheumatoid arthritis (RA) and postmenopausal osteoporosis (PMOP) are common bone-immune diseases. The imbalance between helper (Th17) and regulatory T cells (Tregs) produced during differentiation of CD4+ T cells plays a key regulatory role in bone remodelling disorders in RA and PMOP. However, the specific regulatory mechanism of this imbalance in bone remodelling in RA and PMOP has not been clarified. Identifying the regulatory mechanism underlying the Th17/Treg imbalance in RA and PMOP during bone remodelling represents a key factor in the research and development of new drugs for bone immune diseases. In this review, the potential roles of Th17, Treg, and Th17/Treg imbalance in regulating bone remodelling in RA and PMOP have been summarised, and the potential mechanisms by which probiotics, traditional Chinese medicine compounds, and monomers maintain bone remodelling by regulating the Th17/Treg balance are expounded. The maintenance of Th17/Treg balance could be considered as an therapeutic alternative for the treatment of RA and PMOP. This study also summarizes the advantages and disadvantages of conventional treatments and the quality of life and rehabilitation of patients with RA and PMOP. The findings presented her will provide a better understanding of the close relationship between bone immunity and bone remodelling in chronic bone diseases and new ideas for future research, prevention, and treatment of bone immune diseases.

Identification of CD8+ T cell-related biomarkers and immune infiltration characteristic of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune rheumatic disease, which do not respond well to current treatment partially. Therefore, further in-depth elucidation of the molecular mechanism and pathogenesis of RA is urgently needed for the diagnosis, personalized therapy and drug development. Herein, we collected 111 RA samples from Gene Expression Omnibus (GEO) database, and conducted differentially expressed genes and GESA analysis. Abnormal activation and imbalance of immune cells in RA were observed. WGCNA was utilized to explore the gene modules and CD8+ T cell-related genes (CRGs) were chosen for KEGG and GO analysis. Besides, to explore biomarkers of RA in depth, machine learning algorithms and bioinformatics analysis were used, and we identified GDF15, IGLC1, and IGHM as diagnostic markers of RA, which was confirmed by clinical samples. Next, ssGSEA algorithms were adopted to investigate the differences in immune infiltration of 23 immune cell subsets between RA and healthy control group. Finally, optimal classification analysis based on consensus clustering combined with ssGSEA algorithms were conducted. GDF15 was revealed that to be positively correlated with mast cells and type 2 T helper cells, but negatively correlated with most other immune cells. On the other hand, IGHM and IGLC1 were negatively correlated with CD56dim natural killer cells, while positively associated with other immune cells. Finally, RA samples in subtype A exhibited a higher immune infiltration status. This study could provide guidance for individualized treatment of RA patients and provide new targets for drug design.

Koumine alleviates rheumatoid arthritis by regulating macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

The imbalance between M1-and M2-polarized macrophages is one of the major pathophysiological changes in RA. Therefore, targeted macrophage polarization may be an effective therapy for RA. Koumine, an alkaloid monomer with the highest content and low toxicity in Gelsemium elegans Benth., has the effect of treating RA by playing an immunomodulatory role by influencing various immune cells. However, whether koumine affects macrophage polarization in RA and the associated molecular mechanisms remain unknown.

AIM OF THE STUDY

To investigate the mechanism of the anti-RA effect of koumine on macrophage polarization.

MATERIALS AND METHODS

The effect of koumine on macrophage polarization was investigated in vivo and in vitro. We first explored the effects of koumine on AIA rats and detected the levels of M1/M2 macrophage polarization markers in the spleen by western blotting. Then, we explored the regulatory effect of koumine on M1/M2 macrophage polarization and the effect on the PI3K/AKT signaling pathway in vitro. Finally, we verified the effects of koumine on macrophage polarization in CIA mice.

RESULTS

We found that koumine alleviated symptoms, including relieving pain, reducing joint redness and swelling in AIA rats and restoring the M1/M2 macrophage balance in vivo. Interestingly, koumine had an inhibitory effect on both M1 and M2 macrophage polarization in vitro, but it had a stronger inhibitory effect on M1 macrophage. In a mixed polarization experiment, koumine mainly inhibited M1 macrophage polarization and had an inhibitory effect on the PI3K/AKT signaling pathway. Finally, we found that koumine had therapeutic effects on CIA mice, regulated macrophage polarization and inhibited the PI3K/AKT signaling pathway.

CONCLUSIONS

Our results reveal that koumine regulates macrophage polarization through the PI3K/AKT signaling pathway. This may be one of the important mechanisms of its anti-RA effect, which provides a theoretical and scientific basis for the possible clinical application of koumine.